
public class User {
    private Integer id;
    private String username;
    private String password;
    public User(Integer id,String username,String password){
        this.id = id;
        this.username = username;
        this.password = password;
    }
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
// 重写toString方法
public String toString(){
    return id + "/" +username;
}
    
}